## This file is part of the 'stringi' package for R.
## Copyright (c) 2013-2017, Marek Gagolewski and other contributors.
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#' @title
#' Query Default Settings for \pkg{stringi}
#'
#' @description
#' Presents current default settings used by the \pkg{ICU} library.
#'
#' @param short logical; whether or not the results should be given
#' in a concise form; defaults to \code{TRUE}
#'
#' @return If \code{short=TRUE}, then a single string containing
#' information on default character encoding, locale, and Unicode
#' as well as \pkg{ICU} version is returned.
#'
#' Otherwise, you a list with the following components is returned:
#' \itemize{
#' \item \code{Unicode.version} -- version of Unicode supported by the \pkg{ICU} library;
#' \item \code{ICU.version} -- \pkg{ICU} library version used;
#' \item \code{Locale} -- contains information on default locale,
#' as returned by \code{\link{stri_locale_info}};
#' \item \code{Charset.internal} -- always \code{c("UTF-8", "UTF-16")};
#' \item \code{Charset.native} -- information on default encoding,
#' as returned by \code{\link{stri_enc_info}};
#' \item \code{ICU.system} -- logical; indicates whether system \pkg{ICU} libs
#' are used (\code{TRUE}) or if \pkg{ICU} was built together with \pkg{stringi}.
#' }
#'
#' @export
#' @family locale, encoding
stri_info <- function(short=FALSE) {
   stopifnot(is.logical(short), length(short) == 1)

   info <- .Call(C_stri_info)
   if (info$Charset.native$Name.friendly != "UTF-8") {
#       if (!info$Charset.native$CharSize.8bit)    # this should not cause problems, e.g. in the Big5 encoding
#          warning("You use a non-8bit native charset. " %s+%
#             "This may cause serious problems. Consider switching to UTF-8.")
#       else
      if (!identical(info$Charset.native$ASCII.subset, TRUE))
         warning(stri_paste("Your native charset is not a superset of US-ASCII. ",
           "This may cause serious problems. Consider switching to UTF-8."))
      else if (!identical(info$Charset.native$Unicode.1to1, TRUE))
         warning(stri_paste("Your native charset does not map to Unicode well. ",
            "This may cause serious problems. Consider switching to UTF-8."))
   }

   loclist <- stri_locale_list()
   if (!(info$Locale$Name %in% loclist))
      warning(stri_paste("Your current locale is not in the list of available ",
         "locales. Some functions may not work properly. ",
         "Refer to stri_locale_list() for more details ",
         "on known locale specifiers."))

   if (!short)
      return(info)
   else {
      locale <- info$Locale$Name
      charset <- info$Charset.native$Name.friendly
      return(sprintf("stringi_%s (%s.%s; ICU4C %s [%s]; Unicode %s)",
         as.character(packageVersion("stringi")),
         locale, charset,
         info$ICU.version,
         if (info$ICU.system) "system" else "bundle",
         info$Unicode.version
      ))
   }
}
